Nonleaking lubricant



Patented Mar. 1s, 1937 UNITED 'STATES PATENT ol-Flci-z Roselle Park,

ware

N. J., assi Development Company,

gnors to Standard Oil a corporation of Dela- Application March 29, 1935,Serial N0. 13,616

8 Claims.

The present invention relates to a method for improving lubricating oilsfor industrial uses, and more speciflcally'fory use in small machinery,textile mills and the like. The invention will be 5 understood from thefollowing description.

In the drawing, Figure 1 shows a graphical representation of therelation between oil consumption and power consumption in a journalbearing when used in connection with normal 10 hydrocarbon lubricatingoils and ordinary blended oils; and Figure 2 shows asimilarrepresentation of the comparison of oil consumption and powerconsumption ofthe oils now in use and of the present improvedlubricants. 15 In the lubrication of large machinery such as turbinesand similar equipment. it is economical vto provide methods and devicesfor recovering oil. These generally consist of an oil storage, feed andreturn pipes, and for this reason the o loss of oil is so small as to benegligible. All of the oil is used and its full value is thus realized.In small machines, however, it is rare that such systems are economical,and in textile mills, for example, where there area large number ofsmall 5 independent'bearings to be lubricated, the loss of oil due toleakage is very large, but itis still usually uneconomical to employrecovery methods and apparatus therefor but the loss is objectionablenevertheless. For this reason, it is very desirable, if possible, toprepare oils which will have the least possible leakage tendency.

It is equally important in lubricating oils to employ a suiflciently lowviscosity oil so as to keep the power consumption as low as possiblecom- 5 patible with good lubrication. It is thus found with ordinarystraight mineral oil, oils including oils blended with fatty compounds,soap, aluminum stearate andthe like that increasing viscosities aredesirable .in respect to the oil o consumption, but undesirable inrespect to power consumption. Therefore, in each instance it is a matterof great importance to choose an oil of such viscosity as to give thebest return in respect to both power consumption and oil loss.

i In the present invention it has been found that certain oilcompositions are much morefavorable in respect to oil consumption andpower consumption than the straight mineral or blended oils heretoforeused. This is of especial l importance for textile mills where a largenumber of small machines, looms, for example, are operated with journalbearings and without any device for recovering the oil. the presentcompositions, while adequate for carrying the load, s how greatlyreduced leakage It is found thatwith little or no increase in powerconsumption. Indeed, it is frequently the case that the power consumedis even less than with the normal oil of substantially the sameviscosity.

The type and quality of the base oils may be varied to suit theparticular mill requirements and is, oi course, a mineral lubricatingoil which may be derived from any particular source; for example, fromparaffine or naphthene crudes. 'I'he viscosity may vary throughout therange of the ordinary lubricating oils, say from about 75 seconds toapproximately 2,000 seconds Saybolt at 100 F., depending on the loadrequirements for the particular bearings and other factors.

To the base oil is added a very small quantity, say less than .5% of alinear hydrocarbon poly- -mer of isobutylene which is soluble in the oiland which is characterized by a molecular weight in excess of 30,000,this Weight being determined by the Staudinger method, DieHochmolekularen organischen Verbindungen, H. Staudinger, 1932, Berlin.The actual amount of the polymer used in any particular depends to someextent on the particular circumstances, but quantities as low as .001%may be satisfactory, especially where the molecular weight of thepolymer is very high, say above 100,000 and it is rare that more than.5% is ever used. For ordinary uses .1% is satisfactory.

The preferred polymer is produced from isobutylene which has beencarefully purified and polymerized at a temperature below 50 C. andpreferably at temperatures from -80 to -1l0 C. in the presence of activemetal halide catalyst such as boron fluoride, although other catalystsmay be employed. VThe low temperatures may be readily attained bycarrying out the reaction in the presence of liqueed ethylene andallowing the same to evaporate at atmospheric pressure fory example. Itshould be understood that there is an entire series of linearisobutylene polymers ranging in molecular weight from below 1,000 and upthrough the range indicated above. but there is a critical molecularweight which marks off the polymer satisfactory for the presentpurposes. Polymers having molecular weights below about 30,000 whenadded to the oil merely increase viscosity and the blends showan yoilleakage-power consumption relation comparable to that displayed by awhen polymers above 30,000 are used, a totally different effect is notedand the oil consumptionpower consumption relation is vastly Vdifferentfrom that shown by normal cils of the normal unblended hydro-- carbonoil of the same viscosity yrange. However, t

same viscosity. The polymers which are used, as stated before, havemolecular weights above 30,000 and they may be as high as 100,000,200,000 or even more.

A second ingredient of the oil is a soap. For this purpose the sodasoaps are preferable. not only because ot their cheapness but alsobecause of their superior effects in the oil. Sodium oleate may beusedor similar salts of other fat acids such as stearic or palmitic, ormixtures of the same. Similarly, the alkali metal salts of syntheticacids may be used, particularly those prepared by the low temperatureoxidation of oils and waxes. The amount of the soap is quite small andis ordinarily less than 1% or 2%. As little as .1% shows a substantialeffect, but .5% is usually employed.

While the soap is not an absolutely essential ingredient of the presentcompounds, the latter are greatly improved by their addition. Forexample, in many cases the addition of the polymer to the oil will bringabout a substantial decrease in oil consumption, but in many cases itbrings about also a slight increase in power consumption. However, onthe addition of the soap. it is usually found that both the oil and thepower consumption are considerably reduced. These eiects, whilenoticeable in oils of all the viscosity ranges, are most noticeable inthe range from say 200 to 900 seconds Saybolt. Blends of oil and soap,which do not contain the polymer do not show the reduction of leakage.

The above substances are the principal ingredients of the presentcompounds although it will be understood that other agents may be added,for example, higher alcohols, glycerine or glycol, fatty acids oresters. or other polar compounds which have the property of reducingfrictional losses. Resins vmay also be added for certain purposes, aswell as aluminum soaps such as naphthenate, oleate or stearate or dyes,oxidation or pour point inhibitors none of appear to interfere with theeiIect of the primary ingredients.

To illustrate the operation of the improved oils and'the advantages ofthese compositions, the following examples may be considered.

Example 1 A large number oi' tests on straight minerals and mineral oilsblended with soaps, fatty substances and the like were run on a bearingwhich consisted of a one-inch diameter steel shaft in a bronze sleeve offour-inch length. The oil was fed at the center of the sleeve and thenallowed to leak at the ends. This'oil that leaked out was collected andleakage thus determined in cubic centimeters per minute. The runs wereconducted at a speed of 1,200 R. P. M. obtained by means of `a D. C.motor, and power consumption was measured by the difference in wattageconsumed by the motor and the bearing, and by the motor alone. y

It was found in general that power consumption increased with viscosityand oil consumption decreased therewith. The entire eifect appears to bea viscosity phenomenon. The power consumption when plotted againstleakage made a fairly smooth curve which is represented in Figure 1 ofthe drawing. Since there was no attempt to control all of the variables,such as temperature and the like, the curve is shown but the deviationfrom the mean was not great which drawing and was undoubtedly within theexperimental error at all times. Care was taken to insure that thebearing and motor were in substantially the same condition during all ofthese comparable tests.

In the above tests. the oil and oil blends represented on the curvevaried in viscosity from to 1,200 seconds Saybolt at 100 F. and samplesincluded straight mineral oils of that viscosity range, mineral oils,oils containing lard oil, sodium and potassium oleates or other soaps,aluminum stearate, sodium or calcium sulfonates, rosln and the like. Itwill be seen that the particular composition of the oil did not have anysubstantial effect on the relation between oil consumption and powerconsumption.

Example 2 having viscosities of about 200, 500, and 900 sec-v ondsSaybolt at 100 F. respectively, and similar oils containing .1% of anisobutylene polymer, having a molecular weight of 60,000 to 100,000together with .2% of sodium oleate.

The oil leakage and power consumption tests were carried out accordingto the same procedure used in Example 1 and the data are plotted inFigure 2 of the drawing, curve A representing the straight mineral oils,while curve B represents the oils containing polymer and soap. The widedillerence between the leakage and power consumption in the presentcompositions and the straight mineral oils can be readily seen from theExample 3 Data. some of it included in Example 2, on oils, unblended oiland oil blended with the soap alone or with the polymer alone and withthe combinatiglns of soap and polymer are shown in the table The presentcompositions do not show any undesirable eilects which would in any wayhinder their employment for the most exacting uses. For example, it isfound that the present oils can be scoured from clothes which they havestained without the slightest dimculty. In practical tests it is-foundthat over 99% could be removed without difilculty and that they areequal to ordinary mineral oils in this respect. The oils have excellentlubricating properties suicient to carry such loads as will be normallyapplied to them in textile mills. They are also quite stable toward heatand the eiects of air.

These oils may also be used in conjunction with emulsiers, colloidalmaterials such as graphite, clay, zinc oxide, etc., sludge dispersers.low molecular weight oil thickeners, volitalized oils, waxes, extremepressure agents, organometallic compounds, and the lik 'I'he oilsprepared according to may in many cases be employed this invention insoluble oil compositions for oiling textile fiber cordage,

leather and similar materials.

The present invention is not to be limited by any theories of theadvantages of the present oils nor to any specific composition,rmolecular weight of polymer, or speciilc soap or combination ofingredients, but only to the claims in which inherent in the We claim:

1. A lubricating oil adapted for low power consumption and leakage,comprising a mineral oil lubricating oil and a small quantity, less than.5% of an oil soluble linear polymer of isobutylene lubricating oilhaving a viscosity'in the ran e of about to 2,000 seconds Saybolt at 100F., and less than .5% of an oil soluble linear polymer of viscosity fromabout 200 at 100 F., less than .5%

isobutylene having a molecular weight in excess -ot 30,000.

3. A lubricating oil according to claim 2 in which the polymer has amolecular weight within the range from 30,000 to 300,000 and is present,

in proportion within the limits of .001 to .5%.

4. A lubricating oil according to claim 2 in which the polymer has amolecular weight within the range from 30.000 to 300,000 and is .presentin an amount from .001 to .1%.

5. An improved consumption and leakage comprising a mineral lubricatingoil having a viscosity in the range of 75 to 2,000 seconds Saybon at 1ooF., a, small quantity, less than .5% of an oil soluble linear polymer ofisobutylene having a molecular weight in excess of 30,000 and a smallquantity of an alkali metal soap.

6. A composition according to claim 5 in which a sodium soap is used.

7. A lubricating oil for low power consumption and leakage comprising amineral oil having a to 900 seconds Saybolt of a polymer of isobutylenehaving a molecular weight in excess of 30,- 000 and less than .1% of asodium soap.

8. A composition according to claim 7 in which the amount of polymer isbetween .001 and .1%

`and the amount of soap is between .1 and 1%.

JOHN c. z i. EJNAR, W. cARLsoN.

lubricating oil of low power`

